An additional black box is opened when running this program.

[mhanhmk]

When I use this to write a local application, running the exe file opens a black window screen.

[13r0ck]

That's called the windows command prompt. It's really useful for debugging software. If your code has a print statement in it, you will see it there.

It can be disabled by adding #![windows_subsystem = "windows"] to your code like this, but you probably want it there while you develop your application.

[mhanhmk]

I got it, thanks for the answer.